Gravity: It's Universal

We owe our lives to gravity. It holds the atmosphere to Earth and keeps us all from falling off into space. Not to mention that without gravity, the stars and planets—including Earth—wouldn't even exist!

More About This Resource...

This Moveable Museum article, available as a nine-page printable PDF file, introduces the key concepts of gravity, orbits, weight, and weightlessness. It discusses the following five concepts in depth, and provides a reading list for further research:

gravity is the universal force of attraction between all matter

weight is a measure of the gravitational force pulling objects toward Earth

objects seem "weightless" when there is nothing holding them up

an orbit results from a combination of the forward motion of an object and the force of gravity

astronomers use the law of gravity to analyze distant phenomena

Teacher Tip

Supplement a study of astronomy with an activity drawn from this Moveable Museum article.

Ask the class what they know about gravity. What role does it pay in the universe? What would life on Earth be like without it?

Send students to this online article, or print copies of the essay for them to read.

Have them briefly explain each of the four concepts in their own words.